1. Field of the Invention
The present invention relates to an optical modulator, an optical device and a projector.
2. Description of Related Art
Conventionally, there has been known a projector having a plurality of optical modulating devices that modulate a light beam irradiated from a light source in accordance with image information to form an optical image, a color-combining optical device that combines and irradiates the light beam modulated by the optical modulating device, and a projection optical device that projects the light beam combined by the color-combining optical device in an enlarged manner.
As an optical modulating device in such projector, for instance, an active matrix driven optical modulator has been widely used. Specifically, the optical modulator includes: a pair of boars including a driving board disposed on a light-irradiation side, the driving board having a data line, a scan line, a switching element, a picture electrode, etc. for applying drive voltage to a liquid crystal, and an opposing board disposed on a light-irradiation side, the opposing board having a common electrode, a black mask, etc.; a liquid crystal layer including electrooptic materials such as liquid crystal sealed between the pair of boards; and a flexible printed board extending from between the pair of boards to output predetermined drive signals to the scan line, the data line, the common electrode, and the like.
At the light-incident side and the light-irradiation side of the optical modulator, an incident-side polarization plate and an irradiation-side polarization plate transmitting a light beam with a predetermined polarization axis are respectively disposed.
When the light beam irradiated from the light source is irradiated on the optical modulator, the optical modulator tends to be subjected to the temperature rise due to light absorption of the data line and the scan line formed on the driving board and the black matrix formed on the opposing boards as well as light absorption of the liquid crystal layer. Further, out of the light beams emitted from the light source and transmitted through the optical modulator, the light beam not having the predetermined optical axis is absorbed by the incident-side polarization plate and irradiation-side polarization plate, which easily causes generation of heat on the polarization plates.
Therefore, for projectors having such optical elements therein, an arrangement having a cooling device using a cooling fluid has been proposed for restraining temperature rise of the optical elements (see, for example, Reference: JP Hei 1-159684A).
The cooling device disclosed in JP Hei 1-159684A includes a cooling chamber supporting the optical modulator and a polarization plate at the light source side in a spaced manner and having the cooling fluid filled therein. The cooling chamber is intercommunicated with a radiator and a fluid pump through a tube or the like capable of delivering the cooling fluid through the inside thereof. Thus, the internal cooling fluid circulates in a flow path from the cooling chamber to the radiator, the fluid pump, and back to the cooling chamber through the tube. With such arrangement, the heat generated on the optical modulator and the incident-side polarization plate due to the light beam emitted from the light source is released to the cooling fluid.
In the cooling device disclosed in JP Hei 1-159684A, for instance, when the tube or the like is intercommunicated with an end in the direction as the extension direction of the flexible printed board of the optical modulator in the cooling chamber, the tube needs to be installed so as not to interfere with the flexible printed board, in other words, to avoid contact with the flexible printed board to connect the radiator, the fluid pump, and the like.
Therefore, in such case, a troublesome work is necessary in installation of the tube or the like.